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O Oshima

Publications and source records attributed to O Oshima.

11 recordsLinked to original sources
PubMed1994

Expression of collagen species in a cartilaginous tumor derived from a human osteogenic sarcoma.

We have succeeded in transplanting human osteogenic sarcoma into nude mice. Morphologically, the transplanted tumor is chondrosarcoma and manifests calcification, but not ossification. This tumor is thought to be an excellent model for studying the process of morbid endochondral calcification. In this study, we have used in situ hybridization to examine expression of collagen type I, II, and III mRNAs in this tumor. In situ hybridization was carried out using biotinylated DNA probes. Hybridized probes were detected using a streptavidin-biotin-alkaline phosphatase reagent. The results showed that collagen type I and II mRNAs were produced by cells of the transplanted tumor. Collagen type I mRNA was chiefly localized in the marginal region of the tumor. Collagen type II mRNA, which was predominantly found in the premineralized region of the transplanted tumor, gradually decreased toward the mineralized region. Collagen type III mRNA was not expressed in the transplanted tumor. These results suggest that the character of progenitor chondrogenic cells might be transferred to the transplanted tumor, and that the tumor cells may change the expression of collagen genes with the differentiation or maturation.

Animals↗
PubMed1992

Lymphocyte subsets in immune-mediated otitis media with effusion.

To examine the role of T-cell subsets in immune-mediated otitis media with effusion induced by keyhole limpet hemocyanin (KLH), we used immunohistochemical methods to investigate the kinetics of immunocytes of the middle ear (ME) and eustachian tube (ET) in healthy BALB/c mice. Antibodies against murine macrophages and granulocytes (anti-Mac-1), helper T cells (anti-Lyt-1), suppressor T cells (anti-Lyt-2), immunoglobulins (anti-IgG, -IgM, -IgA), secretory component (SC) and KLH were used. The ME exhibited a substantial immune response, whereas the response of the ET was minor and was associated with a secondary ME immune response. After KLH challenge, an effusion with an extensive infiltration of inflammatory cells (Mac-1, IgG+ and IgM+ cells) was observed at days 1 and 3 in the ME cavity and rapidly disappeared by day 7. Within the ME mucosa, a large number of cells was observed at days 1 and 3, peaking on day 7 when a submucosal lymphoid infiltration was detected. In the immune response of the ME mucosa, Mac-1 cells were the predominant cell type followed by helper T cells, IgG+ cells, IgA+ cells and then IgM+ cells. Suppressor T cells were rarely detected after KLH challenge. SC was present within ME epithelial cells from days 1 to 14.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Localization of types I, II, and X collagen in the transplanted tumor derived from human osteogenic sarcoma.

We have succeeded in transplanting human osteogenic sarcoma of the mandible into nude mice. As the transplanted tumor shows features of calcified chondrosarcoma, this tumor is thought to be an excellent model for study of the process of dystrophic endochondral calcification. Using this model, we studied relations between the expression of types I, II, and X collagen and chondrogenic differentiation of the transplanted tumor. Collagen distribution during the development and growth of the transplanted tumor was investigated by immunofluorescence with specific antibodies against type I, II or X collagen. Type X collagen was intensely stained in the mineralized region. Almost all tumor cells in this region were hypertrophic. Type II collagen was chiefly distributed in the unmineralized region where tumor cells showed chondrocytic or hypertrophic feature. These results indicate that the type of collagen changes from type II to type X in the hypertrophic region and the type X collagen may be synthesized by hypertrophic tumor cells. Type I collagen was localized in the marginal region of the tumor, though it disappeared in the mineralized region.

Adult↗
PubMed1990

Changes in osteonectin distribution and levels are associated with mineralization of the chicken tibial growth cartilage.

Osteonectin is a calcium-binding matrix protein thought to play a role in regulating calcium distribution in a variety of biologic processes. To examine its role in endochondral bone formation, we examined the distribution of the protein during mineralization of the chicken tibial growth cartilage, using immunohistochemistry and immunoelectron microscopy. The synthesis of osteonectin was also determined in chondrocyte populations isolated from premineralizing and mineralizing regions of growth cartilage and assayed in short-term culture. The results show that a very low level of osteonectin is detectable in the resting, proliferating, and early hypertrophic zones of growth cartilage; in these zones, osteonectin is largely cell-associated. In contrast, a large amount of osteonectin is present in the mineralizing zone where it is associated with the matrix. Biosynthetic data from short-term culture experiments indicate, however, that osteonectin is synthesized and secreted by chondrocytes from both premineralizing and mineralizing zones. As indicated by immunoprecipitation, Northern hybridization, in vitro translation of hybrid-selected messenger RNA (mRNA), and electrophoretic analysis, osteonectin synthesized by chondrocytes of the premineralizing zones is not obviously different in structure from that synthesized by chondrocytes of the mineralizing zone. We conclude that osteonectin is a product of chondrocytes in each zone of growth cartilage but accumulates only in the mineralizing zone. The high affinity of the protein for calcium could favor its retention in calcifying matrix.

Animals↗
PubMed1990

Hypertrophic chondrocytes. The terminal stage of differentiation in the chondrogenic cell lineage?

Chondrocytes emerging in the limb or other locations during embryogenesis are currently considered terminally differentiated cells and thus represent the last stage of differentiation in the chondrogenic cell lineage. Most chondrocytes, however, undergo further major phenotypic changes during late embryogenesis and early postnatal life as they take part in the endochondral ossification process. During this process, "resting" chondrocytes first enter an active, proliferative phase and then develop into large, round hypertrophic chondrocytes with unique phenotypic traits. The question thus arises as to whether hypertrophic chondrocytes actually represent the terminal stage of differentiation in the chondrogenic lineage. To assess the developmental position of these cells along the lineage, we examined the expression of four genes encoding extracellular matrix components in chondrocytes undergoing endochondral ossification in chicken tibial growth cartilage. We found that the steady-state levels of mRNAs coding for proteoglycan core protein increased in regions of cartilage destined for endochondral ossification. Similarly, type II collagen gene expression increased markedly in proliferating chondrocytes and then returned to basal levels in hypertrophic chondrocytes. As revealed by in situ hybridization, type X collagen gene expression was undetectable in resting and early proliferating chondrocytes and was detectable in hypertrophic chondrocytes. Osteonectin synthesis appeared to characterize chondrocytes in the resting, proliferating, and hypertrophic zones of growth cartilage. The protein was scarce, however, and cell-associated in the former zones, although it was very abundant and matrix-associated in the hypertrophic zone. Clearly, the emergence of hypertrophic chondrocytes during endochondral ossification is accompanied by marked quantitative and qualitative changes in gene expression. Interestingly, these changes occur during or immediately after the period of active chondrocyte proliferation. On the premises of the cell lineage definition proposed by Holtzer, the above data suggest that the hypertrophic chondrocytes represent the terminal stage of differentiation in the chondrogenic cell lineage.

Animals↗
PubMed1989

Developmental expression of genes in chick growth cartilage detected by in situ hybridization.

We have used in situ hybridization to examine expression of collagen type I, II, and X mRNA and osteonectin mRNA in the chick epiphysis. Tissue samples from the proximal tibial growth cartilage were fixed in modified Carnoy's solution, dehydrated in ethanol, and embedded in paraffin. Longitudinal and transverse sections were demineralized with HCl and digested with hyaluronidase and proteinase K. In situ hybridization was carried out using biotinylated cDNA probes; the hybridized probe was detected using a streptavidin-biotinylated alkaline phosphatase conjugate. This procedure permitted detection of the corresponding mRNAs in cartilage with high sensitivity and low background. Osteonectin mRNA was detected in proliferating cartilage; lower levels of osteonectin mRNA were seen in the mid-hypertrophic region. This mRNA species was also expressed in cells that border the vascular canals in the premineralized region of the epiphysis. Collagen type X mRNA was detected throughout the hypertrophic zone. As localization of collagen type X mRNA corresponded to the site of maximal synthesis of the protein, reported in other studies, our results would further support the suggestion that this protein is associated with mineralization of cartilage. Collagen type II mRNA was seen in both the proliferating and the hypertrophic regions of the cartilage. Highest levels of expression were observed in the proliferative region. The results suggest that the transcriptional control of collagen type II and X by cells of the proliferating and hypertrophic regions of the growth cartilage may be related.

Animals↗
PubMed1988

Gene expression in mineralizing chick epiphyseal cartilage.

To map transcriptional events associated with mineralization in developing long bones, we have established protocols for preparing RNA from regions of chick epiphyseal cartilage. Using these RNA preparations, we have probed for appearance of mRNA coding for type I, II, and X collagen, as well as osteonectin and calmodulin. Type II collagen mRNA was found in proliferating cartilage and, in lower amounts, in hypertrophic/calcifying cartilage. Type X mRNA was absent from proliferating cartilage and present in hypertrophic/calcifying cartilage at steady state levels slightly lower than that of type II mRNA. Type I mRNA was the major collagen mRNA species in endochondral bone; however, significant amounts of type X mRNA were also found. Examination of type X/type II ratios suggest that the cells producing type X mRNA in bone are different from those in the hypertrophic/calcifying cartilage region. Osteonectin mRNA was present in endochondral bone; however, significant amounts were also detected in precalcified cartilage. Indeed, the level of osteonectin mRNA was significantly higher in the resting/proliferating region than in the hypertrophic/calcifying region of the cartilage. No correlation was observed between calmodulin mRNA and the development of mineralization; levels of this message were slightly lower in endochondral bone, embryonic sterna, and calvaria than they were in chick liver and considerably lower than the calmodulin mRNA levels in chick brain.

Animals↗
PubMed1988

Linkage between energy status of perivascular cells and mineralization of the chick growth cartilage.

The objective of this investigation was to investigate the relationship between the energy status of epiphyseal chondrocytes of the chick growth cartilage and the development of mineralization. A microfluorimetric scanning technique was used to measure the reduced pyridine nucleotide content of transverse sections of freeze-trapped cartilage; these measurements were related to tissue structure by scanning electron microscopy. The results of this study show that the energy status of cells in the hypertrophic region of the growth cartilage is more complex than was previously believed. In hypertrophic cartilage, most chondrocytes are in a reduced state. However, in the early hypertrophic region, the vascular channels that penetrate the cartilage from the metaphysis exert a profound local effect on the energy metabolism of perivascular chondrocytes. Thus, around each of the channels, there exists a zone of chondrocytes about 40-60 micron wide which exhibits a low fluorescence yield. The fluorescence level suggests that these perivascular cells have a higher level of oxidative metabolism than hypertrophic chondrocytes that are a distance (greater than 150 micron) from the vascular channels. This finding, in conjunction with our earlier observation that mineralization is first seen in the perivascular region, leads us to the conclusion that mineralization is associated with cellular oxidative activity. We now reject the long-held concept that in cartilage the development of mineralization is entirely due to tissue hypoxia.

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